X-ray control apparatus



June 21, 1960 F. x. MONALLY 2,942,114

X-RAY CONTROL APPARATUS Filed Feb. 19, 1958 535,1, F|q.l '0

Film 22 Hold" T m m 2| go '7 OoMrol l8 5 E Dovlco Tlmor 25 20 Control Flg. 2 v Device Timer 2O Control 3 O Dovico United States Patent X-RAY CONTROL APPARATUS Frank X. McNally, Baltimore, Md., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 19, 1958, Ser. No. 716,143

3 Claims. (Cl. 250-35) The present invention relates to X-ray control apparatu's, in general, and more particularly to timing control apparatus for controlling the radiation from an X- ray source.

The present invention has particular relation to the timing of X-ray exposures by means of photoelectric control apparatus in which an organic fluorescent member is positioned within the path of an X-ray beam after it has passed through an object to be X-rayed, and a light responsive device such as a phototube is provided to receive the light energy fromthe fluorescent member and, in turn, is connected to a suitable control circuit for controlling the time duration of the radiation from the X-ray source. The latter control circuit can be readily adjustable for controlling the radiation from the X-ray source relative to the density of the object exposed to the X-rays and is operative, to assure that suflicient radiation will pass through the object to be X-rayedfor adequate exposure of the provided film.

The physical limitations of the restricted space in an X-ray table intended for both fluoroscopy and radiography are such that a light energy responsive device such as a phototube cannot be reasonably positioned within the radiation path from the X-ray source. Also prior art devices using particularly cadmium sulfide were undesirable.

Accordingly, it is an object of the present invention to provide improved photoelectric timing apparatus for use in controlling radiations from an X-ray source for controlling particularly the time duration of such radiations.

it is another object of the present invention to provide improved phototiming apparatus for controlling the radiation from an X-ray source, which control apparatus can be utilized within a restricted space, and particularly the space provided in a fluoroscopic table or the like.

It is a different object of the present invention to provide improved monitoring orphototiming apparatus for controlling the radiation from an X-ray source without interfering with a fluoroscopic or radiographic image produced by said radiation.

It is an additional objectof the present invention to provide improved phototiming apparatus for controlling and monitoring the radiation from an X-ray source rela-. tive to only a particular area covered by said radiation and with a minimum of interference by undesired radiation relative to other areas covered by said radiation other than said particular area.

it is a further object of the present invention to provide improved phototiming control apparatus having a thickness which allows a fluorescent member made of organic material and of adequate area to be provided within the restricted space and provided within the path of radiation in a fluoroscopic table, and which phototiming control apparatus is so constructed that substantially all of the light emitted from the fluorescent member is concentrated by a light conducting member made of 2,942,114 Patented June 21, 1960 organic material on a remotely positioned light receiving device to thereby provide a greater sensitivity to" the radiation within-said restricted space for accurately timing the radiation from said X-ray source.

It is still another object of the present invention to provide improved phototiming apparatus for controlling the radiation from an X-ray source, which control apparatus is relatively simple and economical to manufacture and is readily employed with presently existing X- ray equipment without requiring modification or changes of said existing X-ray equipment.

Still another object is to provide a relatively planar phototimer apparatus having an X-ray monitoring portion having a thickness relative to the thickness of a light conducting. second portion such that no observable and objectionable image is provided by said apparatus.

These and other objects and advantages of the present invention will become still more apparent from a study of the following description taken in conjunction with the accompanying drawings, wherein: i

Figure 1 is a diagrammatic View illustrating control apparatus in accordance with the present invention positioned relative to other well-known pieces of equipment 'utilized for X-ray fluoroscopy and radiography;

Fig. 2; is a top view of the present control apparatus illustrating one modification of the control apparatus;

Fig. 3 is a top view of the control apparatus in accordance with the present invention illustrating. a further modification; and

Fig. 4 shows a further application of the present control apparatus.

The controlapparatus of the present invention is useful in particular for phototiming an X-ray radiograph.

In Fig. 1 there is shown a source of X-rays 10 positioned to provide radiation through an object 12 to be X-rayed and a well-known bucky grid 14 to a film holder device 16 on which the desired X-ray image is formed. The control apparatus in accordance with the present invention includes a monitoring device 17 positioned within the X-ray path and which comprises a light conducting member 18- provided with a recess or hole therein containing a light producing member made of fluorescent material 20, which fluorescent material 20 is responsive to radiation from the X-ray source 10 passing through the object 12 and the spot film' device 16. The light conducting member 18 may be covered with an opaque lacquer 21 to provide a light-tight enclosure surrounding the entire light conductor member 18 other than on one side of the light conducting member leading to a phototube 22'. In this regard, the opaque lacquer 21 may be in the form of a light reflecting material such that light generated by the fluorescent member 20 is reflected and contained within the light conducting member and directed toward the phototube 22. A

A second source of X-rays 24 is shown in position relative to the light conducting member 18 to illustrate the restricted space between the fluoroscopic screen 16 and the second source of X-rays 24, which restricted space is not suflicient for the phototube 22 to be positioned conveniently therein.

In Fig. 2 there is illustrated a modification of the control apparatus in accordance with the present invention, wherein the light conducting member 18 is provided with a recess or hole within which is positioned. the light producing fluorescent member or material 20. One-half of the hole provided within the light conducting member 18 on the side away from the phototube 22 is provided with a light reflecting material 25 such that light energy from the fluorescent material 20 travelling in a direction away from the phototube 22 strikes the reflecting mate rial 25 and is redirected toward the phototube 22. In

member 18 and similar surfaces 27 on the other side of the light conducting member 18 which are angled such that light energy from the fluorescent material 20 is reflected by said surfaces in a direction toward the phototube 22. a

In Fig. 3 there is shown a still additional modification of the control apparatus in accordance with the present invention wherein the. light conducting member 18 is provided with arecess containing a fluorescent member 20 and the end 28 or edge of the light conducting member 18 away from the phototube 22, is shaped in accordance with a parabolic curve and is operative to direct light energy from the fluorescent material 20 in a direction toward the phototube 22 to thereby concentrate the light energy on the phototube 22.

Thusly, it will be noted that the control apparatus in accordance with the present invention provides an X-ray fluorescent material member 20 in the path of radiation from the X-ray source'10 and includes a light conducting member 18 for directing the light energy from the fluorescent material 20 toa light energy receiving device such as a phototube 22 without interfering with the fluorescent or radiographic image produced by' the radiation from the X-ray source. In this regard both of these members 18 and 20 may be made of materials having substantially the same X-ray absorption properties. The light conducting member 18 may comprise a flat, light energy transparent plastic plate having a thickness of approximately to A of an inch and having an area exposed to radiation as large as the desired exposed area of the film holder device 16.- The plastic material utilized should not fluoresce or react to the radiation from the X-ray source. A hole or recess is cut in the plastic plate over the particular or predetermined area where it is desired to measure or monitor the X-ray radiation. This hole may be filled with fluorescent material responsive to the radiation from the X-rays to provide light energy, with said material being preferably transparent to said light energy. The entire light conducting member 18 with the fluorescent member 20 contained within the recess or hole in the light conducting member 18 may then be covered with an opaque lacquer or light reflecting material such that a light-tight construction is thereby provided having only one side opening onto the light receiving device 22 such as the phototube, so that the only light energy which can actuate the light receiving device 22 is that light energy resulting from the X-rays passing through the fluorescent member 20. The light energy so. created within the light transparent fluorescent member travels directly through the fluorescent member 20 and through the light conducting member 18 to the light receiving device 22 for providing an outmaterial 20 should preferably put control signal as a function of or proportional to the Iight'energy provided by the fluorescent member 20. The control signal from the light energy receiving device 22 may energize a suitable timer control device 23 for controlling the time duration and/ or the quantity or the -radiation from the X-ray source 10 through the power supply 29 operative with the X-ray source 10.

In this'manner, the film holder device 16 activated by the radiation from the X-ray source 10 can be observed and operated as Well known in this art without interference and still be monitored by the fluorescent member 20 contained in the recess or hole provided within the light conducting member 18.

In this regard, stray radiation from the X-ray source 10 striking other parts of the light conducting member 18 other than the area of the fluorescent material 20 will not produce visible light, and hence, will not aflect the monitoring of the predetermined area desired to be monitored and which area is defined by the predetermined area of the fluorescent member 20.

As an example of suitable materials which can be utilized in accordance with teachings of the present invention, the light conducting member 18 may be made present invention, a radiation monitoring or detecting device can be interposed in the beam of radiations from the X-ray source and absorb the radiation over a predetermined area with additional control means or apparatus being provided to monitor the X-ray radiation relative to said predetermined area without placing the latter said control apparatus in the direct path of. radiations from the X-raysource relative to the film holder 16; It should be here noted that the areato be'monitored can be varied by proportionally varying the exposed area of the fluorescent material 20 as'may be desired.

In the modification of the control app'aratusas shown in Fig.2, the reflectingmaterial 25 may comprise white lacquer or aluminum foil such that the light energy from the fluorescent member 20 travelling in a direction away from the phototube 22 strikes the reflecting member 25 and is redirected toward the phototube. 22 to aid in actuating the phototube 22.

In Fig. 4 there is shown thefilm holder device '16 posi tioned relative to a fluorescent screen 19, with the monitoring device 17 in accordance with the present invention positioned between the film holder device 16 'and a bucky grid 14, if the latter-grid 14 is desired.

Although the present invention has been described with a certain degree of particularity, it should be understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the scope and spirit of the present invention. if

' I claim as my invention:

1. In apparatus for controlling theradiation from an X-ray source as entering vertically into a thin horizontally-extending space, a thin plate-like light-transparent member disposed in said space and having a horizontal area of exposure to X-radiation as large as the desired exposure area of an adjacent film holder, a phototube disposed in light communication with an edge of said light:

transparent member so that'said light-producing memher will not produce a shadow on a film. g

2. In apparatus for controlling the radiation from an X-ray source as entering vertically into a thin horizon tally-extending space, a thin plate-like light-transparent member disposed in said space and having a horizontal area of exposure to X-radiation as large asthe' desired exposure area of an adjacent film holder, a phototube disposed at an edge of said light-transparent member to look horizontally into said space, and a light-producing member oflight-transparent fluorescent material responsive to X-rays disposed in said light-transparent member in direct view by said phototube, said light-producing inember being disposed the aforesaid horizontal area r G of exposure of said light-transparent member and having edge in light communication with the phototube has a an area smaller than said area of exposure and having surface which reflects the light from the light-producing substantially the same X-ray absorption property within member inwardly. its area of exposure as that of said light-transparent mernher so that said light-producing member will not produce 5 I References Cited m the file of flus patent a shadow on a film UNITED STATES PATENTS 3. Apparatus according to claim 1 wherein the 2,695,964 Schepker Nov. 30, 1954 boundary of the light-transparent member other than the 2,765,411 Kerr Oct. 2, 1956 

